FIG. 1 shows a block diagram of a conventional cellular radiotelephone communication system 5 which includes cells 6, radio base stations or cell sites 8, and a Mobile Telephone Switching Office (MTSO) or mobile telephone switching center 9. As a mobile telephone customer 7 moves from one cell to another, a switch in the MTSO 9 automatically switches connections with the respective radio base stations 8 to maintain a continuous connection with the public switched network (not shown). Typically, a switch in a Mobile Switching Telephone Office is connected to approximately one hundred cell sites.
A problem associated with the management of a cellular radiotelephone communications system is geographically locating an area within the zone of radio coverage or cell where faulty coverage exists. For example, an area within a cellular telephone system may provide poor service due to moderate levels of interference. Typically, this situation is discovered through customer complaints or a persistent drive team testing by system operators. Neither of these approaches, however, provides very timely or comprehensive means of identifying, diagnosing, and curing faulty coverage.
In response to these deficiencies, the cellular industry has turned to the aid of electromagnetic coverage prediction tools to assist in the search for holes in the coverage. Typically, such methods of monitoring system performance include observing downlink information along with other system parameters. The term “downlink” signals from the cell site to the mobile unit and the term “uplink” means signals traveling from the mobile unit to the cell site. Observing the downlink connection provides evidence of the status of the uplink connection. The assumption is that if the downlink was closed (i.e., a good connection was attained), the available uplink power would be sufficient to close the uplink.